Steering mechanism of road vehicles



1 I e I March F. w. LANCHESTER STEERING MECFKANISM 01 110111) VEHICLES Filed Sept. 9. 1926 2 Sheets-Sheet 1 March 27 F. w. LANCHESTER STEERING MECHANISM OF ROAD VEHICLES Filed Sept. 9. 1926 2 Sheets-Sheet 2 Patented Mar. 15, 1927.

LUNEETZE PA TIE" ret ree 'i' iQiEF-IZCZE.

HEREDERIQK .WILLIAMHLANCHESTEB, .OF..MOSELEY, .BIB-MINGHAM, ,ENGLAND.

STEERING MECHANISM. OFiROAD" VEHICLES.

1 Application filed-September 9, 1926, Serial' 1 l0.'

:Dhe present:invention relates to improvewHlBIltS: in: the steering mechanism of. powerpropelled road vehicles and refers more particularly to/an improved damper adapted to be embodied in suchwmechanism whose funccommonly referred rtov as wheel wobble or 1 shimmy.

It has been proposed to employ a simple damping device or dash-pot to control the wsteering .mechanism'for the purpose incli- :ca-ted. It has been fnr-ther, proposed to employ a device comprising valves in conjunction with the dash-pot adapted to free the steering mechanism when operated from the steering handwheel, but which remain closed and leave the a damper functionally operativeagainst' pivotal-movements of the road 1 wheels when initiated by roughness or potholes in the road or other extraneous cause.

134,557, and in'Great Britain October 3, 1925.

fpay OH? or straighten out after turning a corner. The leakage for this purpose may he madeadjustable bya-by-pass Controlled bya regulating screw or may be determined onceand for all by the degree-of'fit of the piston and amountof-leakage permitted past same.

' shaft 0 is furnished'wi-th a radi'alcprojec- The object of the present" invention is in v -mechanism ofithe latter type to minimize theextent of" free movement required to operate the valves andsg-ivea free passage'for liquid to flow from one side of the damper piston to the other. lit is necessary, if a steering mechanism is-to act perfectly at -high-speeds, that the backlash between the -operating'handwheel and road wheels should be reduced to the minimum possible.

Beferri-ngto the accompanying diagrammatio 1dra-w ings:--

Figure 1 is a plan view partly, in section of a' convenient construction in accordance with the present invention, certainduplicate parts being omitted, and

Figure 2 is across-sectional view on the line A-A of Figure 1, and

Figure 3 illustrates in plan the device applied to a steering axle.

In one mode of carrying the present invention into efiect as illustrated in Figures 1 to 3, I provide a damper, preferably of the semi-rotary type, coupled directly or indirectly to the steering linkwork, the piston a of the said damper being a sufficiently close fit within the segmental cylinder (15, Figure 3) to prevent the rapid movement of the steering road wheels about their pivots, but with suflicient leakage to allow of the said wheels moving slowly under the influence of road reaction to allow the steering gear to 1 a spring 72 and gives vent to a common chainupper-end of whicha' lever connected by a" In the example illustrated the piston is made. integral with a hollow shaft b-to the link to one of the couplingrarms-iskeyed andv through the hollow shaft-is arranged an actuating shaft 0 controlled by linkwork from the steering handwheel. The actuating tion or arm (Z housed within the pistonaforesaid and in the walls of the piston won either 7 side of the arm (Z are provided two pairs of primary valves having a very small moveinent, one pair being shown at e, f, while the corresponding duplicate pair is omitted.

The valve is closed on its seat by a spring 9 and the projection on the actuating arm cl acts on the head of the inner valve 6 when the steering handwheel is operated in -one direction, thus closing the valve 6- on to its seat and at the same time opening the valve 7.

A similaraction occurs as regards the "duplicate valves (omitted from the drawings) when the steering handwheel is operated in the reverse direction.

:From a chamber h providedas shown between the said valve seats a-duct j is carried to a cylindrical cavity machined in the body of the piston, and withinthis cylin drical cavity a-secondary piston mis fitted arranged to operate asecondary-valv'en I opening outwards in association with a'fixed seating 0. This valve is normally closedwby her orlduct q so that upon-the--secondary valve or being lifted by pressure admitted from the corresponding primary valve oil or other liquid can pass through the said valve by way of the common duct and through the other identical secondary valve (not shown) which opens automatically against its spring.

It will be understood that-an identical.

primary valve, secondary valve, spring,

seating and duct are provided in respect of the left-hand part of Figure 2 although these are omitted from the drawings for the sake of clearness. l

The primary valves may conveniently be 'made each in two parts, as illustrated, that is to say, two valves 6, f whose stems accurately butt the one on the other, this prono way of escape other than by leakage. The

ducts (j) communicating with the primary valves (6, 7?) remain in communication with I the space r in which the. actuating projectionor arm is housed and this space is vented through a to the common duct 9 of the secondary valve system so that the pres sure cannot rise above that on the side of the vpiston which is not under pressure ex- 'cept so tar as due to the secondary valve springs (72). is operated it moves, say, the primary valves When, however, the arm (Z c, 7, closing the connection between the ductj and the housingspace 'r and opening the said duct to the pressure side of the piston a. Pressure is thereby admitted to the secondary piston m controlling the secondary valve nwhichopens to the pressure side of V the damper piston and so allows the oil to ner' may be arranged to control the secescape and pass through the damper piston,

the opposite secondary valve opening against "its spring automatically.

The movement permitted to the primary valve, 7 may be as little as a few thousandths ot' an inch, theamount of oil having to pass same being only sufiieient to operate one or other of the secondary valves and this motionwhich appears as back-lash in the steering handwheel becomes negligible in comparison with that necessary to open a valve of suflicient area directly.

If desired, in order to still further limit the duty performed by the primary valves,

intermediate valves operating in like man ondary valves,'but for ordinary purposes an area adequate tor the passage of 011 can be obtained with a simple primary and secondary system as hereinbefore described.

The device is shown in Figure 3 mounted upon a front axle 2 to which stub axles 3, 4 carrying wheels 5, 6 are pivoted The piston a operating within the segmental cylinder 15 is rigid with an arm 7 and the latter is coupled to the arms 9, 10 on the stub axle mountings by links 11 and 12 respectively. The arm (Z, however, is ri 'id with an arm 13 which is coupled by a link 14 to the steering control mechanism (not shown).

Having now described my invention what I claim as new and desire to secure by Letters Patentisz- 1. Hydraulic steering damping mechanism including in combination a damper piston, a cylinder therefor, a duct through said piston, a pair of damping release, valves controlling said duct, hydraulic power operating means on said piston for each of. said valves, an auxiliary valve on said piston associated with each of said hydraulic power operating means and means for man ually actuating said auxiliary valves alternatively as required.

2. Hydraulic steering damping mechanisin including in combination a damper pis ton, a cylinder therefor, a duct through said piston, a pair of damping release valves controlling said duct, a hydraulic piston as sociated with each of said valves and operating in a cylindrical bore in said damper piston, a two-part auxiliary valve controlling each of said cylindrical bores and means for manually actuating said auxiliary valves alternatively as required.

3. Hydraulic steering damping mecnanism as claimed in claim' 1 including also a further passageway through said damper piston constituting a constricted hydraulic g connection.

4-. Hydraulic steering damping mechanism as claimed in claim 1 including also a r iturther pair ot valves interposed between the respective damping release valves and auxiliary valves. 1 i

in testimony whereof I have signed my name to this specification.

FREDERICK WlLlilAll l LANCHESTERI 

